PARIS — Eli Lilly, the American pharmaceutical giant, said on Tuesday that it had received European approval to sell its new drug for treating Type 2 diabetes, putting pressure on its Danish rival Novo Nordisk, the market leader in its category.

The European Commission approved the drug, Trulicity, after a positive recommendation in September from the European Medicines Agency committee that reviews pharmaceutical products for human consumption, Lilly said in a statement from Indianapolis, where it is based. Trulicity will be in European pharmacies next year, the company said.

About 387 million people worldwide are thought to have diabetes, a condition in which the body does not produce enough insulin or is not able to use it efficiently. Within the overall numbers, the incidence of the Type 2 variety, which is often associated with obesity, unhealthy diets or a lack of exercise, has been rising at epidemic rates.

People with Type 1 diabetes must have daily insulin injections to survive. Many of those with Type 2, who make up more than 90 percent of those with diabetes, can control their condition with exercise and changes in diet, but some need drugs to help manage their blood sugar.

Trulicity belongs to a category of drugs called GLP-1 receptor agonists, also known as incretin mimetics. Such drugs act by mimicking the body’s own glucagon-like peptide-1, a natural hormone, which increases insulin production and slows digestion. Lilly’s new drug will compete directly against the leader in the class, Victoza, made by Novo Nordisk.

Victoza, whose generic name is liraglutide and which has been on the European market since 2009 and on the United States market since 2010, is second among Type 2 diabetes drugs, behind Merck’s Januvia, which belongs to a separate class of drugs known as DPP-4 inhibitors.

A Food and Drug Administration panel in September recommended that another version of Novo Nordisk’s liraglutide, called Saxenda, be approved for use as a weight-loss drug in the United States, although the agency has not yet decided on the matter.

Analysts at Datamonitor Healthcare, a market research company, estimate that the market for the GLP-1 class will be worth more than $10.5 billion a year by 2022. They predict that Trulicity will overtake Victoza in 2020.

Trulicity’s once-a-week dosage by injection gives it an advantage over Victoza, which must be injected daily.

Sherry Martin, a senior medical director at Lilly, said in an interview in September that creating a weekly injection became possible after researchers at the company learned to attach an immunoglobulin molecule to the actual GLP-1 receptor agonist, creating “a very large molecule that is minimally cleared by the kidneys, giving it a half-life” in the body of about five days.

Dr. Martin said that the idea of using an immunoglobulin molecule to extend the half-life of drugs was not new, but that Trulicity was the only GLP-1 so far to use that mechanism.

The labeling for Trulicity contains a warning regarding increased risk for thyroid C-cell tumors based on studies in rats. The risk to humans is not certain.

The most common side effects reported include mild nausea and, when Trulicity is used in combination with insulin, low blood sugar. As a condition of authorization, the company must continue monitoring patients for complications.

Trulicity has been approved by the European regulators for use as a stand-alone treatment or for use in tandem with other treatments. It is injected with a proprietary pen, which contains a concealed needle, and can be taken at any time of day, with or without meals.

Correction:Nov. 25, 2014

An earlier version of this article referred incorrectly to the status of the drug liraglutide in the United States. In September, an F.D.A. panel recommended approval of Novo Nordisk’s liraglutide that is called Saxenda as a weight-loss drug; at that time, the full F.D.A. did not approve Novo Nordisk’s liraglutide formulation Victoza, which has been on the United States market since 2010.

Correction:Nov. 27, 2014

An earlier version of this article misstated the way in which the drugs known as GLP-1 receptor agonists act. They act by mimicking the body’s own GLP-1, not by stimulating the production of it.